Volume 19, Issue 3, Pages 370-382 (September 2016) The Central Nervous System Regulates Embryonic HSPC Production via Stress- Responsive Glucocorticoid Receptor Signaling  Wanda Kwan, Mauricio Cortes, Isaura Frost, Virginie Esain, Lindsay N. Theodore, Sarah Y. Liu, Nadine Budrow, Wolfram Goessling, Trista E. North  Cell Stem Cell  Volume 19, Issue 3, Pages 370-382 (September 2016) DOI: 10.1016/j.stem.2016.06.004 Copyright © 2016 Elsevier Inc. Terms and Conditions

Cell Stem Cell 2016 19, 370-382DOI: (10.1016/j.stem.2016.06.004) Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 1 Zebrafish Embryos Exposed to Serotonin or Fluoxetine Have Increased HSPC Formation (A) WISH for runx1/cmyb in the AGM following exposure to serotonin (7 μM) and fluoxetine (30 μM) from 12−30 hpf. (B) Qualitative phenotype distribution of embryos (n ≥ 20 embryos/condition, ≥3 replicate experiments) from (A) scored with increased (up), normal, and decreased (down) runx1/cmyb expression in the AGM of control, serotonin (Sero)-, and fluoxetine (Fluox)-treated embryos. Up, yellow bar; normal, white bar; down, red bar. (C) Representative images of Tg(runx1P1:egfp) embryos at 30 hpf demonstrating increased Runx1+ HSPCs with serotonin and fluoxetine treatment (white arrowheads). (D) qPCR analysis showing serotonin (Sero) and fluoxetine (Fluox) significantly increased runx1 gene expression at 30 hpf (n ≥ 6 replicates of 30 pooled embryos/condition). (E) Representative images of Tg(flk1:dsred;cmyb:egfp) embryos showing dual-labeled (yellow) HSPCs (white arrowheads) at 48 hpf. (F) FACS analysis of (E) (n ≥ 15 replicates of 5 pooled embryos/condition). (G) HSPC WISH following serotonin and fluoxetine exposure from 24−30 hpf (runx1/cmyb) in the AGM and 48−72 hpf (cmyb) in the CHT. (H) Qualitative phenotype distribution of (G) scored as in (B). Data are mean ± SD; one-way ANOVA, Holm-Sidak post hoc: ∗p < 0.05, ∗∗p < 0.01. Scale bars, 100 μM. See also Figure S1. Cell Stem Cell 2016 19, 370-382DOI: (10.1016/j.stem.2016.06.004) Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 2 HSPC Production Is Reduced by Chemical and Genetic Inhibition of Tryptophan Hydroxylase (A−C) p-CPA-treated embryos (50 μM) had decreased HSPCs as demonstrated by (A) representative images and (B) qualitative phenotype distribution of runx1/cmyb WISH at 30 hpf, and (C) FACS analysis of Flk1:dsRed+cMyb:GFP+ HSPCs at 48 hpf (n ≥ 12 replicates, mean ± SD; two-tailed t test: p < 0.05). (D) Representative images of HSPCs in embryos injected with MOs to tph1a, tph1b, tph1a+b, tph2, and tph all as marked by runx1 WISH at 30 hpf. (E) Qualitative phenotype distribution of (D). (F) Representative cmyb WISH images at 48 hpf for embryos injected with MOs as in (D). (G) Qualitative phenotype distribution of (F). (H and I) FACS analysis of (H) CD41:GFPlo and (I) Flk1:dsRed+cMyb:GFP+ HSPCs at 48 hpf showing sustained HSPC deficits in tph2 morphants but not that of tph1a/1b (n ≥ 6 replicates; mean ± SD; one-way ANOVA, Holm-Sidak post hoc: ∗p < 0.05, ∗∗∗p < 0.001). (J) Serotonin (7 μM) rescued Flk1:dsRed+cMyb:GFP+ HSPCs in tph2 morphants at 48 hpf by FACS analysis (n ≥ 22 replicates; mean ± SD; two-way ANOVA, Holm-Sidak post hoc: ∗p < 0.05). Scale bars, 100 μM. See also Figures S2 and S3. Cell Stem Cell 2016 19, 370-382DOI: (10.1016/j.stem.2016.06.004) Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 3 Selective Ablation of Serotonergic Neurons Decreases HSPCs (A) Serotonergic neurons were effectively ablated upon Mtz treatment (10 mM,12−72 hpf) in tph2:nfsb-mcherry embryos as marked by tph2 WISH at 72 hpf. Scale bar, 200 μM. (B) Representative images of cmyb+ HSPCs in the CHT of WT and tph2:nfsb-mcherry fish after treatment as in (A). Scale bar, 100 μM. (C) Expression of cmyb was significantly decreased by qPCR at 72 hpf in tph2:nfsb-mcherry embryos with Mtz treatment compared with the control (Con) (n ≥ 4 replicates). (D) Qualitative phenotype distribution of cmyb and rag2 expression in tph2:nfsb-mcherry embryos at 72 hpf and 5 dpf, respectively. (E) Representative images of rag2+ lymphoid cells in WT and tph2:nfsb-mCherry fish treated from 12 hpf to 5 dpf with Mtz. Scale bar, 200 μM. (F) Expression of rag2 was significantly decreased by qPCR in tph2:nfsb-mcherry embryos by Mtz treatment at 5 dpf (n ≥ 3 replicates). Data are mean ± SD; two-way ANOVA, Holm-Sidak post hoc: ∗p < 0.05. See also Figure S4. Cell Stem Cell 2016 19, 370-382DOI: (10.1016/j.stem.2016.06.004) Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 4 The Effect of Serotonin on HSPCs Is Independent of the Sympathetic Nervous System (A) Representative images of th1 WISH at 72 hpf, demonstrating ablation of catecholaminergic neurons at the sympathetic ganglion (boxed) by 6-OHDA (200 μM) and nepicastat (30 μM) with or without serotonin (7 μM). (B) Representative images of cmyb+ HSPCs in the CHT at 72 hpf in embryos treated with serotonin in the absence or presence of 6-OHDA and nepicastat. (C) Qualitative phenotype distribution of (B). (D−G) qPCR analysis at 72 hpf showing that serotonin significantly increased cmyb expression in the absence or presence of 6-OHDA and nepicastat, whereas genes within the SNS (th1, dbh, ngfb) are unaffected (n ≥ 4 replicates; mean ± SD; two-way ANOVA, Holm-Sidak post hoc: ∗p < 0.05, ∗∗p < 0.01). ns, not significant. Scale bars, 100 μM. See also Figure S5. Cell Stem Cell 2016 19, 370-382DOI: (10.1016/j.stem.2016.06.004) Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 5 Serotonin Activates the Hypothalamic-Pituitary-Adrenal/Interrenal Axis during HSPC Formation (A) Schematic of the HPA/I axis. (B and C) Serotonin (7 μM) significantly increased HPA/I axis genes (B) by qPCR (n ≥ 3 replicates) and total cortisol in the whole embryo (C) by ELISA at 30 hpf (n ≥ 6 replicates; mean ± SD; two-tailed t test: ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001). (D) WISH for runx1 in the VDA following treatment with the GR agonists hydrocortisone (HC, 25 μM) and dexamethasone (Dex, 1 μM) from 12−30 hpf. (E) Qualitative phenotype distribution graph of (D). (F) FACS analysis showing significant increases in Flk1:dsRed+cMyb:GFP+ HSPCs in hydrocortisone- and dexamethasone-treated embryos at 48 hpf (n ≥ 12 replicates; mean ± SD; one-way ANOVA, Holm-Sidak post hoc: ∗p < 0.05). (G−I) Hydrocortisone and dexamethasone treatment (48−72 hpf) increased HSPCs, as shown by (G and H) WISH for cmyb in the CHT and (I) qPCR analysis of cmyb gene expression at 72 hpf (n ≥ 3 replicates; mean ± SD; two-way ANOVA, Holm-Sidak post hoc: ∗p < 0.05). Scale bars, 100 μM. See also Figure S6. Cell Stem Cell 2016 19, 370-382DOI: (10.1016/j.stem.2016.06.004) Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 6 Hypothalamic-Pituitary-Interrenal Axis and Glucocorticoid Receptor Activation Are Required for Serotonin Stimulation of HSPCs (A) Effect of serotonin (7 μM) and hydrocortisone (25 μM) treatment on runx1 WISH in control or nr3c1 MO-injected embryos at 30 hpf. (B) Qualitative phenotype distribution graph of (A). (C) Flk1:dsRed+cMyb:GFP+ HSPCs were significantly increased in serotonin- and hydrocortisone-treated WT embryos but not in nr3c1 morphants at 48 hpf by FACS (n ≥ 15 replicates; mean ± SD; two-way ANOVA, Holm-Sidak post hoc: ∗p < 0.05, ∗∗∗∗p < 0.0001). (D) GR mutant (GRs357) embryos had dramatically decreased runx1 expression in the AGM by WISH at 30 hpf, which could not be rescued by serotonin. (E) Qualitative phenotype distribution graph of (D). (F) Altered WISH for cmyb+ HSPCs in the CHT at 72 hpf and rag2+ lymphoid cells at 5 dpf in the thymus in GR mutant embryos compared with controls. (G) Qualitative phenotype distribution graph of (F). (H) Representative images of CD41+ cells in control and runx1:nr3c1-injected Tg(−6.0itga2b:egfp) embryos at 48 hpf. (I) Cell count of (H) showing increased HSPCs. n ≥ 8; mean ± SD; two-tailed t test: ∗∗p < 0.01. (J) Injection of runx1:nr3c1 construct in GRs357 embryos rescued runx1+ HSPCs at 30 hpf by WISH. (K) Qualitative phenotype distribution graph of (J). (L) MK212 (7.5 μM) could not rescue the HSPC defects seen in crh and pomc MO-injected embryos at 30 hpf by runx1 WISH. (M) Qualitative phenotype distribution graph of (L). (N) FACS analysis of Flk1:dsRed+cMyb:GFP+ HSPCs with treatment as in (L) at 48 hpf (n ≥ 3 replicates; mean ± SD; two-way ANOVA, Holm-Sidak post hoc: ∗p < 0.05). Scale bars, 100 μM. See also Figure S7. Cell Stem Cell 2016 19, 370-382DOI: (10.1016/j.stem.2016.06.004) Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 7 Hypoxic Stress Activates Serotonin Production and the HPA/I Axis via Hif1α to Control HSPC Production (A) Hypoxic signals, as marked by gfp WISH in Tg(phd3:egfp) fish, were present predominantly in the brain at 24 hpf and 30 hpf and could be enhanced by CoCl2 (500 μM) stimulation. (B and C) CoCl2 significantly increased tph2 gene expression (B), but not that of tph1a and tph1b, at 30 hpf (n ≥ 6 replicates), whereas dominant negative hif1a (dnhif1a) mRNA (C) decreased tph2 expression in zebrafish embryos at 30 hpf (n ≥ 6 replicates; mean ± SD; two-tailed t test: ∗p < 0.05, ∗∗p < 0.01). (D) Genes of the HPA/I axis were significantly increased at 30 hpf by CoCl2 treatment (n ≥ 6 replicates; mean ± SD; two-tailed t test: ∗p < 0.05, ∗∗p < 0.01). (E) CoCl2 exposure significantly increased whole-embryo total cortisol production at 30 hpf in control but not in tph2 MO embryos (control versus tph2 MO, ∗∗p < 0.01; n ≥ 4 replicates; mean ± SD; two-way ANOVA, Holm-Sidak post hoc: ∗p < 0.05). (F) The effects of CoCl2 were partially abrogated in tph2 and nr3c1 morphants, as marked by runx1 WISH at 30 hpf. (G) Qualitative phenotype distribution graph of (F). (H) FACS analysis of Flk1:dsRed+cMyb:GFP+ HSPCs in (F) at 48 hpf (n ≥ 7 replicates; mean ± SD; two-way ANOVA, Holm-Sidak post hoc: ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001). Scale bars, 100 μM. Cell Stem Cell 2016 19, 370-382DOI: (10.1016/j.stem.2016.06.004) Copyright © 2016 Elsevier Inc. Terms and Conditions